Anecdotal, but I use Skype for Business every day without any bugs/issues, as does the rest of my company (~50 people, lots of remote workers + liberal WFH policy).
When there's a rare issue, its usually a headset not working, which is probably more a user or windows problem.
I don't see a lot of audio issues, but tons of problems with screen sharing and video.
My company has about 4000 users in 100+ countries so maybe it's bandwidth/scale in part. i see a lot of stuff like skypefb crashes or doesn't render correctly when you try to screen share, etc especially internationally.
Not 100% certain part of it isn't due to us cheaping out on infrastructure to run it.
When there's a rare issue, its usually a headset not working, which is probably more a user or windows problem.